The relationship between population ratio (males aged 15 to 29 years per 100 males aged over 30 years) and conflict severity (death toll per million population per year) from 1980 to 1993 on a logarithmic scale. (
Adapted from Mesquida and Wiener 1995 )

The relationship between the 1989 population ratio (males aged 15 to 29 years per 100 males aged over 30 years) and severity of conflict (total death toll per million population) from 1989 to 1993 on a logarithmic scale. (Adapted from Mesquida and Wiener 1995)

Box

How does testosterone affect aggression?

Although this chapter focuses on
ultimate causes of human warfare, it is just as important to examine
proximate causes in order to fully understand the nature of human aggression, such as the relationship between
testosterone and aggression. Testosterone is the sex androgen believed to be responsible for masculine characteristics, and since females tend to have lower levels of testosterone as well as aggression, testosterone is assumed to have a causal relationship with aggressive behavior. In non-human animals, the hormone is known to be related to aggressiveness, and some studies have found a weak, positive relationship between testosterone levels and aggressiveness in humans as well (Book, Starzyk, and Quinsey 2001; Archer 1991). Testosterone levels have been shown to rise in males before engaging in competitive sports (Mazur and Booth 1998), and levels of testosterone can predict aggression in preschool boys (Sanchez-Martin, Fano, Ahedo, Cardas, Brain, and Azpiroz 2000). However, since studies in humans have largely been corrlational (Archer 1991), the exact nature of the relationship of testosterone in aggressive behavior in humans remains unclear.

The
resource competition theory of coalitionary aggression posits that individual male participants involved in coalitionary acts of aggression gain fitness through an increased access to fitness-enhancing resources, as women prefer to mate with men who are able to provide themselves and potential offspring with these resources (Buss 1989). In this model, aggressive acts may increase fitness either when resources are under the control of a competitor, wherein an aggressor would increase fitness by gaining access to the resource, or when access to a resource is threatened by a competitor, wherein an aggressor avoids a fitness loss by limiting competition (Durham 1976; Buss and Shackelford 1997). Additionally, coalitions of men may also directly compete for access to women; for example, among the Yanomamo tribes have been recorded to raid neighboring groups and kidnap reproductive-aged females (Chagnon 1983 cited by Buss and Shackelford 1997).

In order to determine whether groups of males are more likely to compete over resources or females, researchers Manson and Wrangham hypothesized that when resources are easily monopolized, conflict will likely occur over these resources. However, in circumstances where essential resources are not easily monopolized, conflict will likely occur over females themselves. To ensure that resources are in fact related to reproductive fitness, the researchers also hypothesized that in situations where resources are easily monopolized, the accumulation of wealth will be associated with
polygyny , whereas when resources are not easily monopolized, polygyny will correlate with other factors, such as social ranking or ability to defend family. To test this theory, the researchers analyzed the anthropological literature for ethnographic accounts of autonomous societies dependent on hunting and foraging that at least occasionally engaged in warfare. The researchers recorded whether the societies fought over resources or females, whether resources were easily monopolized, and whether polygyny and wealth were related. Results were consistent with predictions (see
[link] and
[link] ) (Manson and Wrangham 1991).

In this morden time nanotechnology used in many field .
1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc
2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc
3- Atomobile -MEMS, Coating on car etc.
and may other field for details you can check at Google

Azam

anybody can imagine what will be happen after 100 years from now in nano tech world

Prasenjit

after 100 year this will be not nanotechnology maybe this technology name will be change .
maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments

Azam

name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world

Prasenjit

how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?

At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.